AREAS OF THE MEDULLA OBLONGATA 



877 



to the other. At the caudal border of the pons they embrace the pyramidal tracts 

 as well, but farther cephalad the transverse pontile' fibres are seen to intersect 



Valve of 

 Vieussens 



Superior medullary velum Lingida 

 Section of superior^ 

 cerebellar peduncle 

 Sylvian root of trigeminal 



Nerve cells^^a- 

 Posterior longitudinal ^3L 



fasciculus 



Lateral fillet 

 Formatio reticulans 

 Lateral 



Mesial fillet 



Transverse 

 fibres of 

 pons 



Pyramidal 

 fibres 



Trigeminal 

 Pyramidal 

 fibres 



Fourth ventricle: its 

 ependyma in yellow 



Mesial fillet 



Transverse 

 fibres of 

 pons 



Pyramidal 

 fibres 



Trigeminal 



Pyramidal 

 fibres 



Transverse fibres of pons 



Rapht 



FIG. 644. Vertical transverse section of the pons, at its upper part. 



the pyramidal tracts, breaking these up into pyramidal fasciculi; still farther 

 cephalad the pyramidal tracts are wholly embedded in the mass of transverse 



Decussation of trochlear nerves 



Locus caeruleus 



M esencephalic root of 

 trigeminal nerve 



Medial longitudinal 



bundle 



Lateral lemniscus 

 'ower's tract 



Rubrospinal tract 



Beginning of decussation 

 -of superior peduncles 

 of cerebellum 



FIG. 645. Transverse section of pons near its junction with mid-brain. (Higher level than Fig. 644.) ' 



pontile fibres, so that these in turn, with reference to the location of the pyramidal 

 tracts, may be divided into a superficial and a deep set. Laterad they are gathered 

 together to form the middle peduncles (described on p. 892). 



